Distance, temperature and clothing.
Distance depends on what you want to visit or observe, the weight of kit carried, and on your physical condition.
Nowadays (age 66) I reckon 90km is reasonable for me when cycle-camping in moderately hilly terrain, that is about 5 hours at 18 km/h. I'd do the same distance happily in a morning putting in more effort on an unloaded bike at about 22 km/h.
11 years ago I did a 3,300 km tour in 27 days, which is an average of 122 km/day, including the "rest days".
But I trained for several months before going to get my fitness up, and my daily average speed and mileage varied a lot, with a maximum of 205 km in a very flat and relatively uninteresting area of France and much less in the Pyrenees, the Picos d'Europa and other mountainous bits I visited in Spain and Portugal.
Just pootling about on roads, paths and tracks, taking photos and looking at flora, fauna and buildings I was surprised to see that I had done 71 km on one of my "rest" days. I did less on a couple of my "cycling" days, once when it rained heavily and I holed up early in a youth hostel to dry out, another time when it was very hot and I didn't feel like going far.
Shade temperatures ranged from 1°C to 35°C, with a maximum range of 32°C in one day.
I didn't take very much clothing - cycling shorts, cycling tights, merino tops, rain gear and a synthetic microfibre quilted jacket that I didn't use on the bike (synthetic because down doesn't like getting wet, either by rain or by sweat). I took a total of 3 pairs of socks, two thin and one thicker pair made of merino wool. So I washed something most nights.
When very cold I put nearly all of it on, including some lightweight ski gloves (I had been warned to allow for sub-zero temperatures in the mountains). This was OK for 1°C and I could have gone down to about -10°C by adding the quilted jacket, rain trousers, breathable rain jacket and shoe covers.
When hot, just cycling shorts, a long-sleeve merino top and thin socks in my old-fashioned leather cycling shoes. For wearing all day, merino worked better for me than synthetic, as it was still reasonably comfortable when soaked in sweat, either from the heat or from condensation inside (breathable) raingear during heavy rain.